We have users that query our prod database (mostly ODBC through MS-Access) to create some customs reports. We want to copy our data to a second server (replicate / log shipping / ???) so the load on the prod DB is less. Many of the tables in the Prod DB do not have primary keys and is a SQL Server 2005. Our target DB is SQL Server 2012 Standard (though we can down-grade the destination server if we have to).
How could we accomplish that? We've tried replication and failed because of the lack of primary keys. We also tried log-shipping but the second DB cannot be brought online because of the difference in SQL versions.